A firm which runs what is thought to be Britain's largest fishing fleet has admitted a £141,000 quota scam.
Elizabeth Stevenson's firm falsified auction records
Cornwall-based W Stevenson and Sons, which has 35 vessels, admitted 37 charges of filing false sales records.
The family firm is run by Elizabeth Stevenson, who is chair of the National Federation of Fisheries Organisations.
It involved six Newlyn boats catching more than their quota of valuable fish but recording them as non-quota species, Exeter Crown Court heard.
A total of 13 skippers or owners from the six trawlers the Carol H, Girl Patricia, Ajax, CKS, Ben Loyal and Ben Macrae were all either found guilty of or admitted misrecording their catches.
Cod, hake and anglerfish were mis-described as non-quota, lower-value, species such as ling, turbot and bass.
Cod was recorded as lower value, non-quota fish
The Stevenson firm, which runs auctions where the fish are sold, also falsified the auction records to make sure they matched the fiddled figures provided by the skippers.
This enabled them to break the European rules which were designed to save dwindling fish stocks.
Newlyn auctioneer Julian Bick was convicted on four counts of aiding and abetting the Stevenson company.
The Stevenson firm had been found guilty of eight specimen counts of submitting sales notes which did not accurately indicate the quantity of each species landed in October 2006.
It now faces an asset confiscation hearing later in the year.
Mrs Stevenson left court without comment.
FISH QUOTAS GUILTY
Phillip Mitchell, Barney Thomas, Cynthia Thomas of the Carol H
Arthur Williams and Leonard Williams of Girl Patricia
Drew Davies, of CKS
Barney Thomas, Cynthia Thomas and Raymond Knight of Ajax
John Turtle, Donald Turtle and Joan Turtle of Ben Loyal
James Hicks, Jonathan Hicks and Doreen Hicks of Ben Macrea
Paul Trebilcock from the Cornish Fish Producers Organisation said the case could have far-reaching consequences for Newlyn.
He said: "Stevenson are very important to Newlyn.
"A third to half of the fish landed at Newlyn come from Stevenson boats. They act as agents, as fuel suppliers and for a host of other services to the port.
"So to take Stevenson out, whether you like them or loathe them, would cause major trouble for Newlyn as a fishing port."
He said that the Department for Environment, Food and Rural Affairs (Defra), which uncovered the offences, had been "heavy-handed".
He said: "There's been a lot of unnecessary show.
"Maybe it was just a demonstration to Europe that they can police their own fleets, but we view it as a discriminatory regime that we have endured for five years."
He added: "There is no argument about being legal, but there is an argument about the practicality and commonsense of the regulations."
A Defra spokesman said it would continue to prosecute quota offences "robustly".
He said: "It is essential that the fishing industry complies with the regulations which are intended to ensure fish stocks remain sustainable.
"These types of prosecution are necessary in order to protect the livelihoods of fishermen."